Spam Blocking.

Complete Blocking.

Our incoming mailserver now blocks connections from well known sources of SPAM (Unsolicited Commercial E-Mail). In our tests this has reduced the amount of spam by around 80%. We use the spam blocking lists (RBLs) at the Spamhaus Organization and SpamCop.

Also blocked are:

DSL/ADSL/cablemodem/dial-up lines from, mostly non-UK, ISPs who have failed to take adequate measures to protect the internet community from SPAM originating from these sources. Their official mailservers are unaffected by this block.
Servers who have no reverse-DNS entry.
Computers relaying e-mail using a dynamic IP address.

Further Tests.

After the complete blocks above, further analysis is carried out on the mail and the sending host.

We query further RBLs including: Abusive Hosts Blocking List, SORBS and several others.

We also make our own checks, based on information gleaned from the contents of the e-mail headers, including: a "callout" to verify the sender address, a check using GeoLite™ data created by MaxMind™, available from http://www.maxmind.com/ and a dspam check on the message body.

The results of all these tests are given a score. Additional SPAM emails are rejected based on this score.

Notes:

Since no system if foolproof it is possible that legitimate sources of e-mail could be blocked. We can bypass the SPAM checks if so required by individual users. Please get in touch with the postmaster if you experience problems with particular senders unable to deliver mail to you.

Naturally we can only check mail that passes through our server. SPAM may still arrive directly to your ISP's mailbox. The solution is to use a POP3 mailbox on our server and ignore all other sources of mail.

Spamhaus et al maintain lists of IP addresses (computers) which have been identified as sources of spam. When a computer connects to our server it's IP address is checked against the databse. If there is a match then mail relaying by that computer is denied. The sending end will be presented with an explanatory rejection message. It is possible for an 'innocent' computer to be listed, virus infection is one way. The RBL databases have a de-listing procedure, sometimes it is automatic using a time limit and sometimes by direct application.

We DO NOT use the UCEprotect blocklists as they have an unacceptable listing policy.

This system does not currently protect your PCs against viruses. Users of the Windows™ operating system should install a virus scanner to check all incoming e-mails. See also our e-mail policy.

Any server with a static IP can apply for a whitelisting on our servers. Even if they are blocked by any of the above criteria.

Avoiding your own outgoing e-mails being classed spam.

Users who relay mail outwards through our server will not have their mail checked by us (Note however that spamming is against our Terms and Conditions). However at the receiving end it may be scanned by a similar system. Take these steps to avoid your legitimate mail being rejected or discarded:

Always use your ISP's smarthost to relay mail.
Microsoft™ users must use virus scanner to avoid their computer becoming a 'spamming zombie'.
Send e-mails as plain text (not as HTML) where possible.
If you must send executable files, rename them before attaching and sending (see our: e-mail policy).
Configure your e-mail client with care, ensure your "From:" address is correct in every detail.
IT Managers: If you do not have a static IP address (i.e: you use dial-up or ADSL), then use your ISP's smarthost to relay mail rather than relaying directly yourself.
IT Managers: Check the configuration and DNS of your outgoing mailserver, ensure it is correct!

External References from Wikipedia.

Go to the TV Science Ltd. Homepage.

Legal Information. Last update of this page: 11th February 2015. E-Mail: webmaster@tv–science.co.uk